It's a major problem for JVM performance as well. Json encoding is simply fundamentally an expensive thing to do.

One thing that improves performance for the JVM that'd be nice to see in node realm is that JSON serialization libraries can stream out the serialization. One of the major costs of JSON is the memory footprint. Strings take up a LOT more space in memory than a regular object does.

Since the JVM typically only uses JSON as a communication protocol, streaming it out makes a lot of sense. The IO (usually) takes long enough to give a CPU reprieve while simultaneously saving memory.